# Mineral magnetism test

Canonical page: https://lithomap.app/resources/field-tests/mineral-magnetism-test
Last reviewed: September 18, 2026
Page purpose: Original LithoMap field-method reference for human readers, search systems, and language models.

## Direct answer

Use a known magnet on a clean specimen and compare the response at several points. Distinguish strong attraction from weak attraction, and distinguish a specimen that is attracted to a magnet from one that behaves as a magnet itself.

## Why the test works

Minerals differ in magnetic susceptibility because of their composition and atomic structure. Magnetite can respond strongly, while many iron-bearing minerals are only weakly attracted or appear nonmagnetic in a hand test.

A small amount of magnetite can make an otherwise nonmagnetic rock respond. Testing several locations helps detect mixtures instead of assigning the response to every grain.

## Field kit

- Small strong magnet enclosed in a bag or sleeve
- Thread for a suspended-magnet check
- Clean specimen
- White paper for loose grains
- Hand lens and notebook

## Procedure

1. Clean and isolate: Remove loose steel fragments, soil, and obvious manufactured debris. Place small grains on white paper.
2. Approach without contact: Bring the magnet slowly toward the sample. Movement before contact demonstrates attraction more clearly than material merely sticking to the magnet after touch.
3. Compare several points: Test different grains, matrix, coatings, and fresh surfaces. Note whether the response is uniform or localized.
4. Grade the response: Record strong, weak, uncertain, or none using the same magnet and distance. Do not convert a hand test into a numerical susceptibility.
5. Check remanence separately: If relevant, suspend the specimen or use a compass at a safe distance from electronics. Attraction to a magnet and acting as a permanent magnet are different observations.

## Interpreting results

- Strong movement toward a small magnet before contact: Supports abundant strongly magnetic material such as magnetite.
- Weak or localized attraction: May reflect sparse magnetite, an intergrowth, weathering products, or a weakly magnetic mineral. Map the responding spots.
- No obvious response: Rules out only a strong response under the test conditions; it does not show that iron or weak magnetic susceptibility is absent.
- Specimen influences a compass or aligns when suspended: Possible remanent magnetization. Keep away from navigation and electronic equipment and confirm with controlled methods.

## Examples and related guides

- Magnetite: Commonly shows strong attraction and a black streak. — https://lithomap.app/resources/mineral-identification/magnetite
- Ilmenite: Often weaker and variable; intergrowths with magnetite complicate hand tests. — https://lithomap.app/resources/mineral-identification/ilmenite
- Hematite: Usually weak or apparently nonmagnetic in a simple test despite its iron content. — https://lithomap.app/resources/mineral-identification/hematite
- Basalt: May respond because of iron-bearing oxide grains, but magnetism does not identify the whole rock. — https://lithomap.app/resources/rock-identification/basalt

## Common mistakes

- Touching the sample first and mistaking adhesion or trapped grains for attraction
- Using different magnets or distances without recording the change
- Assuming every dark magnetic specimen is magnetite or a meteorite
- Ignoring steel filings, drilling fragments, or magnetic dirt
- Treating a localized magnetic grain as the composition of the entire rock

## Safety and limitations

- Keep strong magnets away from pacemakers and other medical devices according to manufacturer guidance.
- Protect phones, magnetic cards, compasses, watches, and sensitive electronics.
- Bag the magnet so attached grains can be removed without scraping or creating dust.
- Magnetism does not establish that a specimen is safe to handle, valuable, extraterrestrial, or lawfully collectible.

## Frequently asked questions

### Does a magnetic rock mean I found a meteorite?

No. Many ordinary Earth rocks contain magnetite or other magnetic grains. Meteorite evaluation requires texture, density, chemistry, and expert evidence beyond a magnet.

### Why is only one part of my rock magnetic?

Rocks are mixtures. A vein, grain cluster, surface contamination, or altered zone may contain the magnetic material while the rest does not.

### Is hematite magnetic?

Hematite is much less responsive than magnetite in ordinary hand tests. Natural mixtures, heating history, and magnetite inclusions can change the observed response.

## Authoritative sources

- Geology Lesson 2: Global Building Blocks — U.S. National Park Service: https://www.nps.gov/teachers/classrooms/geology-lesson-2-global-building-blocks.htm
- Magnetic susceptibilities of minerals — U.S. Geological Survey: https://www.usgs.gov/publications/magnetic-susceptibilities-minerals
- Minerals and their physical properties — U.S. National Park Service: https://www.nps.gov/subjects/geology/minerals.htm

This method supports preliminary field identification. It is not laboratory confirmation, appraisal, hazard clearance, proof of origin, or permission to collect or alter a specimen.